Optical network, such as OTN (Optical Transmission Network), WDM (Wavelength-Division Multiplexing), SDH (Synchronous Digital Hierarchy) or SONET (Synchronous Optical Network) transmission network has already been widely used in the telecommunication field.
Automatic switched optical network (ASON) is the focus in optical network field these years. ITU-T G.8080 standard proposed the concept of ASON, wherein the function of an ASON is performed by setting special Control Plane (CP). ITU-T G.7713 standard provides the realization framework of distributed call and connection in an ASON network and provides the realization specification for the automatic establishment, modification and deletion of call and connection. Standard such as ITU-T G.7715 provides the realization model and method for the route query of the connection (the description about the route query in the rest part of the invention refers to the route query of the connection, unless declared particularly).
However, the published ITU-T G.7715 and ITU-T G.7715.1 both employ the model in FIG. 1. In this route model, when an ASON network element (NE) needs to query the connection route, the Connection Controller (CC) that is responsible for the connection control (including establishment, deletion, modification, etc.) initiates a route query request (shortly, Route Request) of the connection to the Route Controller (RC) that is responsible for route query and calculation. Based on the request, said RC calls a routing algorithm (one in common use is the Constrained Shortest Path First, CSPF) and calculates the route based on the routing database of the current node and returns the route calculation result (shortly, Route Response) to the CC.
However, the RDB of a node usually hardly owns complete routing information of the entire ASON network; especially when the ASON network includes multiple route domains, the RDB of a node usually only owns information of the local domain. As shown in FIG. 2, when it is needed to establish a connection (as a connection in dash line) between the A node in route domain 1 and the Q point in route domain 6, the model method in FIG. 1 can not satisfy the route query and calculation requirements of said connection, therefore, a new route query method in ASON is needed.